Paulo Sousa's World Cup participation is not in doubt but the Portugal midfielder will not train this week after injuring his right thigh.
He is now a serious doubt for the opening match against the United States on 5 June in Suwon, Korea.
Sousa was injured in the warm-up match against China on Saturday which Portugal won 2-0.
Medical checkups in Macau revealed "no serious harm", team doctor Henrique Jones told reporters.
"He will continue the rehabilitation exercises and will be able to restart training on Friday or Saturday," Jones added.